Let's get you up to speed on the Boston terror investigation. Here's what we know. Government sources tell CNN, preliminary talks are under way to allow the suspected bomber, Dzhokhar Tsarnaev, to avoid the death penalty if, if he talks to federal investigators. They want him to give more information about the attacks.

Meanwhile, investigators are trying to determine if there's a link between the other suspected bomber, Tamerlan Tsarnaev, and this man, William Plotnikov, a Canadian boxer-turned-jihadist. He was killed last year in a shootout with Russian troops. That happened in Dagestan while Tamerlan Tsarnaev was in the region. The investigation of the Tsarnaev brothers has put southern Russia on the map for a lot of people.

Investigators right now taking a hard look at Dagestan and Chechnya. A disturbing trend in that part of the world, the rise of women suicide bombers, known as Black Widows.

Nic Robertson reports from Dagestan.

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NIC ROBERTSON, CNN CHIEF INTERNATIONAL CORRESPONDENT (voice-over): In Dagestan's capital last May, an inferno. Moments earlier, a female suicide bomber, known here as a Black Widow, detonated a bomb at a police checkpoint. Minutes later, another blast. The following day, reveals the full horror. The Black Widow's brother driving a car bomb blew this fire truck apart. Callous timing killing the emergency service workers, just as they arrived to put out the flames.

A brutal conflict spilling over from neighboring Chechnya, playing out as Tamerlan Tsarnaev visited his parents here last year.

(on camera): This is the same checkpoint, but we can't stop here. Back then, the attack struck fear into the security services. According to local journalists, for a while, police were too afraid to patrol. (voice-over): Rassul Kadiev, a terror defense lawyer, tells me Russian authorities are handling the female bombers all wrong.

ROBERTSON: It is a problem that's been around over a decade involving wives of rebels killed by government forces.

KADIEV: When a woman's husband is dead, she has no rights. She can't have a lover or a boyfriend. She can't make any decisions. That's why, if she's religious, she becomes an easy target for suicide recruiters.

(SHOUTING)

ROBERTSON: October 2002, 40 to 50 armed Chechen men and women took more than 800 hostages in one of Moscow's principal theaters. It was Russia's capital's deadliest modern day terror attack and the so- called Black Widows took a leading role, ready to die, detonating huge piles of explosives. By the time the three-day siege was over, more than 170 people, including all of the attackers, were dead.

In 2010, two female suicide bombers attacked Moscow's subway. At least 40 people were killed. One of the attackers, a 17-year-old, fit the Black Widow profile perfectly. Her husband, a rebel leader, had been killed by security forces a few months earlier.

(on camera): Rachmanover (ph) also represents a changing face of the Black Widows. She's from here in Dagestan, not neighboring Chechnya, like so many of the Black Widows before her. It signals a shift in the battle front.

(voice-over): The so-called Black Widows are not holding back. This attack, close to Dagestan's capital, killing five policemen in March last year. A war with women in it, unfolding around Tamerlan Tsarnaev and his mother.

Nic Robertson, CNN, Dagestan, Russia.

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BLITZER: For more on the story, CNN.com.

We'll take a quick break.

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BLITZER: I'm Wolf Blitzer in Washington. Welcome back.

You know Boston is certainly getting a lot of help and support as the city recovers. Every day Bostonians have set up makeshift memorials to the terror victims and money has poured in around the country, indeed around the world for one fund Boston campaign from $30 million so far to help victims and families. But they need more. Celebrities are helping all they can as well. Earlier, CNN's Ashleigh Banfield spoke to the Oscar-winning actor, Kevin Spacey, visiting Boston today. Listen to this.

(BEGIN VIDEO CLIP)

KEVIN SPACEY, ACTOR: We were having a lunch the last couple of days here, all of the places that were greatly affected, business has been affected. It's important to people know they can come down here, it's safe, businesses are ready and happy and the food's awesome. It's just important to get the word out Boston's strong. You know, I kind of feel like we're all Boston.

ASHLEIGH BANFIELD, CNN ANCHOR: Yes.

SPACEY: So it's important that everybody be supportive as they can. Certainly with the doctors and nurses and surgeons I met yesterday, one thing they probably won't admit, a, they're tired and b, they're emotionally affected by it. Just to go and lift their spirits has been really, for me, the whole reason I came. I'm really glad I came.

(END VIDEO CLIP)

BLITZER: Of course, you can still help and you should. Go to CNN.com/impact. CNN.com/impact, learn more ways to help the Boston victims.

By the way, you can see more of Ashleigh's interview with Kevin Spacey, coming up at the top of the hour. Stay tuned for that. Very good interview. Amanda Knox is no longer waiting to be heard. We have new details on her time spent in an Italian prison. Her new book is now out.

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BLITZER: Welcome back. A few stories make headlines now. Los Angeles, the first witnesses in the Michael Jackson wrongful death trial testify today. The family is suing Jackson's concert promoter, AEG Live, for negligence in his 2009 death. They want billions of dollars for money Jackson might have earned on his future tour. Lawyers for the promoter prepared an aggressive defense and warns jurors it's going to get ugly.

George Zimmerman, the man who admits to killing Trayvon Martin back in court, he waived his right to a Stand Your Ground hearing, which might have led to a dismissal of the charges. That's because Florida's Stand Your Ground law allows for immunity if a defendant can prove he acted in self-defense. You may remember, Zimmerman told police he shot the unarmed 17-year-old in self-defense during a struggle over Zimmerman's gun. Today's decision does not prevent his attorneys from arguing for immunity before the trial, which is set to start on June 10th.

Now to another famous defendant, Amanda Knox. Last month the Italian Supreme Court ruled that Knox should stand trial again for the murder of roommate, Meredith Kercher. She's already served four years after convicted in one of the most-watched trials ever. But when the conviction was reverses by an Italian appeals court, she headed home to Seattle and she's been laying low, until now.

Here's CNN's Alina Cho.

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ALINA CHO, CNN CORRESPONDENT (voice-over): In a glossy roll-out, timed to the release of her new book, "Waiting to Be Heard," Amanda Knox is breaking her silence, on the pages of "People" magazine, prime time special on ABC.

AMANDA KNOX, ACQUITTED OF MURDER IN ITALY: I was in the courtroom when they were calling me a devil. I mean, it's one thing to be called certain things in the media and it's another thing to be sitting in a courtroom fighting for your life while people are calling you a devil.

For all intents and purposes, I was a murderer, whether I was or not. And I had to live with the idea that that would be my life.

CHO: Knox, then an American college student in Italy, spent nearly four years in prison after she and her Italian boyfriend were convicted of murdering Kercher Knox's then-roommate. Details emerged of a kinky sex game gone wrong. This is how she responds to Diane Sawyer.

CHO: In "People," the 25-year-old speaks candidly about life in prison.

BETSY GLEICK, EXECUTIVE EDITOR, PEOPLE MAGAZINE: One of the things that sustained her, a family photo album, she's so lonely caressing the pictures.

CHO: So lonely, she thinks about suicide.

GLEICK: She talked about would she do it in the shower. There's a window in the shower it would be fogs up, nobody could see her she would bleed death a peaceful death.

CHO: Two years after convicted, a dramatic turn of events involving bad evidence. Knox was set free, and returned home to Seattle.

KNOX: Thank you to everyone who has believed in me, who has defended me.

CHO: On why she's talking now, she says, I'm not a murder. But in the latest twist, Italy's highest court has ordered a retrial.

SAWYER: What was your reaction when you heard the Supreme Court decision?

KNOX: It was incredibly painful. I felt like after crawling through a field of barbed wire and finally reaching what I thought was the end. It just turned out that it was the horizon and I had another field of barbed wire that I had ahead of me to crawl through.

(END VIDEOTAPE)

CHO: Amanda Knox is not expected to return to Italy for a retrial. By law she doesn't have to be there. But she does, of course, want to win the court of public opinion. Of course, Wolf, too early to say whether that strategy will work. What is clear is as these latest round of interviews will likely sell lots and lots of books -- Wolf?

BLITZER: She got a multimillion advance for writing that book, right?

CHO: she did. $4 million advance. I wouldn't be surprised if this book landed on the best-seller list.

BLITZER: Alina Cho reporting. Thank you.

Catherine Zeta Jones checking into a mental health facility. Dr. Drew weighs in on her battle with bipolar disorder, next hour.

Also coming up, the FCC is tired of people complaining about indecent network TV. It may loosen its standards. How this could mean more nudity on TV.

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BLITZER: Welcome back to the CNN NEWSROOM.

Remember the so-called wardrobe malfunction at 2004 Super Bowl during the halftime show? Part of Janet Jackson's breast was displayed for all the world to see. CBS fined $550,000 for breaking the government's so-called decency rules.

Now the FCC, the Federal Communications Commission, thinking about relaxing those rules.

CNN's Rene Marsh is joining us now.

Some critics say changing the rules would mean F-bombs, nudity on network TV. How is this going to work?

RENE MARSH, CNN CORRESPONDENT: Well, Wolf, this month the FCC announced by way of this public notice that it is thinking about changing the rules for what is considered indecent and subject to punishment or a fine. The FCC is asking the public if off-the-cuff or accidental moments of profanity and nudity should be treated the same as deliberate and repetitive uses of indecent content. So an example of that would be a shock jock who just deliberately is saying a bunch of inappropriate things, just for the sake of ratings for that matter.

Now, some parents and some groups such as the parent television counsel, they say that a rule change would relax indecency standards to the point that broadcast TV will be dirtier. Take a listen.

(BEGIN VIDEO CLIP) DAN ISETT, PARENT TELEVISION COUNCIL: That means near unlimited profane language. It means nudity. It means patently expletory content as the law defines it. It means stuff that simply is inappropriate for kids.

(END VIDEO CLIP)

MARSH: A little over a week ago, at the first Boston Red Sox game following the Boston bombings, Red Sox player, David Ortiz, used the F-word and it made it on to the airwaves. Listen.

MARSH: All right, well, that goes without saying that is certainly not allowed. But the FCC chairman, he personally excused the comment saying it was off the cuff, tweeting that, quote, "David Ortiz spoke from the heart at today's Red Sox game and I stand with Big Papi and the people of Boston."

So some people say that the change in the rules could mean that, you know, those brief accidental use of profanity would go unpunished and they fear that would give net works a shield to hide behind, giving them more leeway to push the envelope a little bit, when it comes to the use of inappropriate content -- Wolf?

BLITZER: How long, Rene, will the FCC take comments on changing these rules?

MARSH: Well, they'll be taking the comments until May 20th. And so far, I can tell you, at last check, there have been 90,000 comments on the web site. Majority of them are people protesting the change. So this is generating a lot of response.

BLITZER: Certainly is.

Rene, thank you very much.

I should point out, as a footnote that $550,000 fine against CBS was tossed out by the United States Supreme Court.

Martha Stewart is making a move online. You might see her pop up as a possible love connection on match.com. That's straight ahead.

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BLITZER: You may not think Martha Stewart is the type to look for love on match.com, but she said she's looking for Mr. Right again and why not be adventurous?

Alison Kosik is joining us now from New York with some really interesting details. (LAUGHTER)

Really? She went on match.com? Is that what you're saying?

ALISON KOSIK, CNN BUSINESS CORRESPONDENT: That's exactly what she did. Wolf, think about it, just because you're a celebrity, it doesn't mean it is easy to find love. Martha says many people she knows have had luck meeting people online, just now she wants in on the action.

She got all this stuff off her chest when she talked to Matt Lauer on "Today" yesterday. Listen to some of the characteristics she's looking for in a guy.

(BEGIN VIDEO CLIP)

MARTHA STEWART, ENTREPRENEUR: Youngish.

MATT LAUER, HOST, TODAY SHOW: Youngish meaning --

STEWART: Youngish, active.

LAUER: OK. But not an age?

STEWART: No.

LAUER: OK.

STEWART: Energetic.

LAUER: Mm-hmm.

STEWART: Outdoors-ish.

LAUER: Mm-hmm.

STEWART: Really smart.

LAUER: Successful?

STEWART: Successful is important, I think, just for him.

LAUER: Because it would be hard for him if he were not successful to --

STEWART: Right. Tallish.

LAUER: Uh-huh. A lot of issues. So you're actively -- you're actively, you know, this is something --

STEWART: I'm always looking. Are you kidding? All women are always looking.

LAUER: For a relationship?

STEWART: Yes. I do. (END VIDEO CLIP)

KOSIK: Stewart has been married for 26 years. That marriage ended in 1987. Then she was in a long-term relationship, on and off, until a few years ago. Then you listen elsewhere in the interview, Wolf, and she said she would like to have breakfast with somebody and would like to go to sleep with somebody.

Martha is a busy lady, so online dating may be the thing for her. Cuts all the work of going out on a date and then finding you don't mesh with the person at all -- Wolf?

BLITZER: Does match.com profile Martha Stewart and show a picture or is all of this a mystery to her date?

KOSIK: So what Martha did is she set up a profile with the help of Match's CEO, Sam Yagin (ph). Even though she was open to including photos of herself, he advised her not to do that, said it would be distracting. Her interests include, quote, "Cooking, dining out, gardening, shopping and travel." So, yes, that sounds just like Martha Stewart, doesn't it?

BLITZER: Yes. I think she should do an episode of millionaire matchmaker. Did you ever watch that show on bravo? That would be lively -- a lively one hour little program if she would like to do that.

KOSIK: And we could even maybe be like the fly on the wall going on her dates with her. That would be interesting too.

(LAUGHTER)

BLITZER: Yes. I would definitely watch that show if she did it. Let's see what happens.

Alison, thanks very, very much.

Want to end this hour with an update on the Boston One Fund, which is raising money for the terror victims. It raised about $30 million so far, more than half of that coming from corporate donations, the rest from public donations. You can donate to the fund by going to onefundBoston.org. I hope you do. This is very, very important.

And this, a sign things are starting to get back to normal in Boston. Overnight crews repainted the Boston marathon finish line over there on Boylston Street. Traditionally, it's fixed up within hours after runners finish the race. This year, for obvious reasons, the painting was delayed by two weeks. Better late, obviously, than never.

Thanks so much. Good luck to everyone in the Boston area. I'll be back later today, 5:00 p.m. eastern, in "The Situation Room." We'll be focusing in on the president's news conference. He made news, a lot of it, at that news conference. We'll go in depth, 5:00 p.m. eastern in "The Situation Room."

That's it for me. I'm Wolf Blitzer. Brooke Baldwin and Jake Tapper pick up our coverage from Boston right now.